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Abstract:

Disclosed is a method of manufacturing a pattern electrode which excels in
electroconductivity, transparency and etching property and a pattern
electrode, the method comprising a step of applying a metal particle
containing solution onto a substrate to form a conductive layer, a step
of pattern printing a metal particle removing solution on a portion of
the conductive layer, which is to be removed, and a step of washing the
resulting printed material, whereby the portion of the conductive layer
on which the metal particle removing solution has been printed is removed
to form a non-conductive portion.

Claims:

1. A method of manufacturing a pattern electrode comprising a substrate
and provided thereon, a conductive layer containing metal particles, the
method comprising the steps of:applying a metal particle containing
solution onto a substrate to form a conductive layer;pattern printing a
metal particle removing solution on a portion of the conductive layer,
which is to be removed; andwashing the resulting printed material,
whereby that portion of the conductive layer on which the metal particle
removing solution has been printed is removed to form a non-conductive
portion.

2. The method of manufacturing a pattern electrode of claim 1, wherein the
metal of the metal particles is silver or copper.

3. The method of manufacturing a pattern electrode of claim 1, wherein the
metal particles are metal nanowires.

4. The method of manufacturing a pattern electrode of claim 3, wherein the
metal of the metal nanowires is silver or copper.

5. The method of manufacturing a pattern electrode of claim 4, wherein the
metal of the metal nanowires is silver.

6. The method of manufacturing a pattern electrode of claim 3, wherein the
metal nanowires have an average long axis length of from 3 to 500 μm
and an average short axis length of from 10 to 300 nm.

7. The method of manufacturing a pattern electrode of claim 1, wherein the
metal particle removing solution contains an organometallic complex salt
and a thiosulfate.

8. The method of manufacturing a pattern electrode of claim 7, wherein the
organometallic complex salt is an organic complex salt of iron (III).

9. The method of manufacturing a pattern electrode of claim 8, wherein the
organic complex salt of iron (III) is an iron (III)-aminopolycarboxylic
acid complex salt.

10. The method of manufacturing a pattern electrode of claim 7, wherein
the metal particle removing solution further contains a water soluble
binder.

11. The method of manufacturing a pattern electrode of claim 10, wherein
the water soluble binder is sodium carboxymethylcellulose.

12. The method of manufacturing a pattern electrode of claim 1, wherein
the pattern printing is carried out so as to form a metal particle
removing solution layer with a thickness of from 10 μm to 2 mm on the
conductive layer.

13. A pattern electrode manufactured according to the method of
manufacturing a pattern electrode of claim 1.

Description:

FIELD OF THE INVENTION

[0001]This invention relates to a method of manufacturing a pattern
electrode which excels in electroconductivity, transparency and etching
property, and a pattern electrode.

TECHNICAL BACKGROUND

[0002]Heretofore, a film of various metals such as Au, Ag and Pt and Cu; a
film of metal oxides such as indium oxide doped with tin or zinc (ITO or
IZO), zinc oxide doped with aluminum or gallium (AZO or GZO) and tin
oxide doped with fluorine or antimony (FTO or ATO); a conductive film of
nitrides such as TiN, ZrN and HfN and a conductive film of borides such
as LaB6 and the like are well-known as transparent conductive
electrodes, and further, various electrodes including a combination
thereof such as Bi2O3/Au/Bi2O3 and
TiO2/Ag/TiO2 and the like are well-known. In addition to the
transparent electrodes described above, a transparent electrode employing
CNT (carbon nanotube) or a conductive polymer has been also proposed (for
example, refer to "Technologies of Transparent Conductive Film", p. 80,
published by Ohmsha, Ltd.).

[0003]However, the films of metals, nitrides or borides described above
and a conductive polymer film are utilized only in a specific
technological field such as electromagnetic wave shielding or in a touch
panel field where even a relatively high resistance is acceptable, since
high optical transparency and high conductivity are incompatible.

[0004]On the other hand, a metal oxide film is predominantly utilized as a
transparent electrode, since it has compatibility between high optical
transparency and high conductivity and excellent durability.
Particularly, ITO is often utilized as a transparent electrode for
various optoelectronics application, since it has good balance between
optical transparency and conductivity, and can easily form a fine
electrode pattern according to a wet process employing a solution as well
as a vacuum process such as sputtering. However, the vacuum process such
as sputtering requires expensive equipment in order to form a transparent
conductive film, while the wet process requires annealing treatment at
high temperature of 500° C. or higher in order to obtain high
conductivity.

[0005]Besides the transparent electrodes described above, there are
proposed a transparent conductive substrate a having random network
structure comprised of self-organizing silver particles (for example,
refer to WO 2007/114076) and a transparent electrode comprised of metal
nanowires with fine meshes (for example, refer to US Patent Publication
No. 2007/0074316). Particularly, metal nanowires employing silver
nanowires provide compatibility between high conductivity and high
transparency, due to high conductivity which silver itself.

[0006]In order to use a transparent electrode as an electrode for various
devices such as an LCD, an electroluminescence element, a plasma display,
an electrochromic display, a solar cell and a touch panel, it is
necessary to form a pattern of the transparent electrode. As a method of
forming a transparent electrode pattern employing metal nanowires, there
are mentioned a method employing a printing ink containing
electroconductive microwires (for example, refer to Japanese Patent
O.P.I. Publication No. 2003-515622) and a method forming a nanowire
pattern according to photolithography (for example, refer to US Patent
Publication Nos. 2005/0196707 and 2008/0143906).

[0007]However, a method of directly pattern printing metal nanowires
lowers electroconductivity due to increase of contact resistance between
the metal nanowires caused by a binder. Patterning according to a
conventional etching method comprises the steps of forming a resist
pattern by a photoresist, imagewise exposing, developing, removing the
resist by etching, and post-processing. In such a patterning, many steps
before and after etching are required, and etching of the resist is
carried out in a solution and therefore is likely to cause expansion or
separation of the resist, which may result in lowering of etching
accuracy. Further, severe temperature control is required. An etching
solution used for etching a silver film is composed mainly of ammonia,
which releases a strong odor and pollutes the working environment. A
strong acid etching solution such as nitric acid has problems in that it
has an adverse influence on the resist and releases a highly toxic gas.
Furthermore, removal of the resist penetrating between the fine metal
nanowire meshes may be insufficient, resulting in lowering of light
transmittance, and on removal of the resist, metal particles or metal
nanowires are also released. As described above, a conventional pattern
formation method is not satisfactory. Dry etching, which is an etching
method other than photolithography, enables high precision patterning,
but is low in processing speed and in processing capability of the
processing apparatus, resulting in cost increase. Besides the above, an
etching method is disclosed in for example, Japanese Patent No. 3173318,
in which a paste containing particulate substances and a solution having
etching capability is applied to a material to be etched, however, this
method requires high temperature and is not applied to a film substrate.
Further, there is no disclosure of metal particles or metal nanowires in
that patent.

SUMMARY OF THE INVENTION

[0008]This invention has been made in view of the above. An object of the
invention is to provide a method of manufacturing a pattern electrode
which excels in electroconductivity, transparency and etching property,
and to provide a pattern electrode manufactured according to the method.

[0009]In the invention, a method of manufacturing a pattern electrode
comprises the steps of applying a metal particle containing solution onto
a substrate to form a conductive layer, pattern printing a metal particle
removing solution on the conductive layer, and then washing the resulting
printed material.

BRIEF DESCRIPTION OF THE DRAWING

[0010]FIG. 1 is a schematic view showing a manufacturing method of a
pattern electrode.

DETAILED DESCRIPTION OF THE INVENTION

[0011]The present invention has been attained by any one of the following
constitutions 1 to 12.

[0012]1. A method of manufacturing a pattern electrode comprising a
substrate and provided thereon, a conductive layer containing metal
particles, the method comprising the steps of applying a metal particle
containing solution onto a substrate to form a conductive layer, pattern
printing a metal particle removing solution on a portion of the
conductive layer, which is to be removed, and then washing the resulting
printed material, whereby that portion of the conductive layer on which
the metal particle removing solution has been printed is removed to form
a non-conductive portion.

[0013]2. The method of manufacturing a pattern electrode of item 1 above,
wherein the metal of the metal particles is silver or copper.

[0014]3. The method of manufacturing a pattern electrode of item 1 above,
wherein the metal particles are metal nanowires.

[0015]4. The method of manufacturing a pattern electrode of item 3 above,
wherein the metal of the metal nanowires is silver or copper.

[0016]5. The method of manufacturing a pattern electrode of item 4 above,
wherein the metal of the metal nanowires is silver.

[0017]6. The method of manufacturing a pattern electrode of item 3 above,
wherein the metal nanowires have an average long axis length of from 3 to
500 μm and an average short axis length of from 10 to 300 nm.

[0018]7. The method of manufacturing a pattern electrode of item 1 above,
wherein the metal particle removing solution contains an organometallic
complex salt and a thiosulfate.

[0019]8. The method of manufacturing a pattern electrode of item 7 above,
wherein the organometallic complex salt is an organic complex salt of
iron (III).

[0021]10. The method of manufacturing a pattern electrode of item 7 above,
wherein the metal particle removing solution further contains a water
soluble binder.

[0022]11. The method of manufacturing a pattern electrode of item 10
above, wherein the water soluble binder is sodium carboxymethylcellulose.

[0023]12. The method of manufacturing a pattern electrode of item 1 above,
wherein the pattern printing is carried out so as to form a metal
particle removing solution layer with a thickness of from 10 μm to 2
mm on the conductive layer.

[0024]13. A pattern electrode manufactured according to the method of
manufacturing a pattern electrode of any one of items 1 through 12 above.

EFFECTS OF THE INVENTION

[0025]The present invention can easily provide a method of manufacturing a
pattern electrode with excellent conductivity, transparency and etching
properties and a pattern electrode manufactured according to the method.

[0026]The pattern electrode manufacturing method of the invention is a
method of manufacturing a pattern electrode formed on a substrate, which
is comprised of a conductive layer containing metal particles. The method
is characterized in that it comprises a step of applying a metal particle
containing solution onto a substrate to form a conductive layer, a step
of pattern-printing a metal particle removing solution on the conductive
layer, and a step of washing the resulting printed material. The
techniques as described in items 1 through 13 above share this
characteristic.

[0027]As an embodiment of the invention, it is preferred that the metal
particles are metal nanowires in view of effectively exhibiting the
effect of the invention. Further, it is also preferred that the metal of
the metal particles is silver or copper.

[0028]It is preferred in the invention that the metal particle removing
solution contains an organometallic complex salt or a thiosulfate. It is
also preferred in the invention that the metal particle removing solution
contains a water soluble binder.

[0029]Next, the present invention and embodiments for carrying the present
invention will be explained in detail below.

[Outline of Pattern Electrode Manufacturing Method]

[0030]The outline of the pattern electrode manufacturing method of the
invention is shown in FIG. 1. FIG. 1 is a schematic view showing a
pattern electrode manufacturing method in which a conductive layer 2
containing metal particles formed on a substrate 10 is treated with a
metal particle removing solution 20, thereby forming a pattern electrode
30. In this method, the portion of a conductive layer 2, onto which the
metal particle removing solution 20 has been applied, is removed (etched)
to form a non-conductive portion.

[0031]The pattern electrode manufacturing method of the invention is one
manufacturing a pattern electrode comprised of a conductive layer
containing metal particles formed on a substrate. The pattern electrode
manufacturing method is characterized in that the metal particle removing
solution is pattern printed on the conductive layer, followed by washing
(water washing).

[Substrate]

[0032]The substrates employed in the present invention are not
particularly limited, and material, shape, structure, thickness or
hardness thereof may be appropriately selected from those known in the
art. Those having a high light transmittance are preferred.

[0033]Examples of the substrates include a polyester resin film such as a
polyethylene terephthalate (PET) film, a polyethylene naphthalate film or
a modified polyester film; a polyolefin resin film such as a polyethylene
(PE) film, a polypropylene (PP) film, a polystyrene film, or a
cycloolefin resin film; a vinyl resin film such as a polyvinyl chloride
film, or a polyvinylidene chloride film; a polyvinyl acetal resin film
such as polyvinyl butyral resin film; a polyether ether ketone (PEEK)
resin film; a polysulfone (PSF) resin film; a polyethersulfone (PES)
resin film; a polycarbonate (PC) resin film; a polyamide resin film; a
polyimide resin film; an acryl resin film; and a triacetyl cellulose
(TAC) resin film. A resin film having a transmittance of 80% or more in
the visible wavelength regions (380-780 nm) is preferably applicable in
the present invention. Among these, a biaxially-oriented polyethylene
terephthalate film, a biaxially-oriented polyethylene naphthalate film, a
polyethersulfone film or a polycarbonate film is preferred from a
viewpoint of transparency, heat resistance, easy handling, strength and
cost, and a biaxially-oriented polyethylene terephthalate film, a
biaxially-oriented polyethylene naphthalate film is more preferred.

[0034]In order to secure the wettability and adhesion property of a
coating solution, the substrate used in the present invention can be
subjected to surface treatment or provided with an easy adhesion layer. A
well-known technique can be used with respect to the surface treatment or
the easy adhesion layer. Examples of the surface treatment include
surface activating treatment such as corona discharge treatment, flame
treatment, ultraviolet treatment, high-frequency wave treatment, glow
discharge process, activated plasma treatment or laser treatment.
Examples of materials for the easy adhesion layer include polyester,
polyamide, polyurethane, a vinyl copolymer, a butadiene copolymer, an
acryl copolymer, a vinylidene copolymer and an epoxy copolymer. When a
film substrate is a biaxially-drawn polyethylene terephthalate film, an
easy adhesion layer having a refractive index of from 1.57 to 1.63, which
is adjacent to the film, reduces reflection at an interface between the
film and the easy adhesion layer and increases transmittance, which is
more preferred.

[0035]Adjustment of a refractive index can be achieved by adjusting
suitably a content ratio of tin oxide sol or a cerium oxide sol which has
a comparatively high refractive index to a binder resin, and then coating
them on the film substrate. The easy adhesion layer may be a single layer
or may be two or more layers thereof in order to increase adhesion
property. A barrier coat layer or a hard coat layer may be beforehand
formed on the film substrate, if required.

[Conductive Layer]

[0036]The conductive layer in the invention is characterized in that it
contains metal particles. The method of forming the conductive layer in
the invention is not specifically limited and it is a liquid phase layer
formation method in which a dispersion solution containing metal
particles is coated on a substrate and dried to form a layer. As the
coating method is preferred a roller coating method, a bar coating
method, a dip coating method, a spin coating method, a casting method, a
die coating method, a blade coating method, a bar coating method, a
gravure coating method, a curtain coating method, a spray coating method
or a doctor coating method. When the surface of the conductive layer is
required to be smooth, a dispersion solution of metal particles is coated
on a first smooth substrate having a releasing property and dried to form
a metal particle layer, and the metal particle layer is transferred on a
second substrate through a resin layer. The resin constituting the resin
layer is not specifically limited as long as it is transparent in the
visible wavelength regions (i.e., it has a high transmittance. The resin
may be a curable resin or a thermoplastic resin, and is preferably a
curable resin. Examples of the curable resin include a heat curable
resin, an ultraviolet curable resin, and an electron beam curable resin,
and among these curable resins, an ultraviolet curable resin is preferred
since the appliance for resin curing is simple, and it excels in
workability. The resin layer is preferably comprised of an acrylic resin
and an epoxy resin, from a viewpoint of transparency. Further, a
conductive layer containing a conductive polymer or metal oxides or a
binder resin layer may be provided as necessary.

[Metal Particles]

[0037]The metal particles in the invention imply particle-shaped metals
having a particle diameter of from an atomic scale to a nanometer (nm)
size. The metal particles have an average particle size of preferably
from 10 to 300 nm and more preferably from 30 to 200 nm. A metal used in
the metal particles in the invention is preferably silver or copper in
view of electrical conductivity. The metal may be silver alone or copper
alone or may be a mixture of silver and copper, an alloy of silver or
copper, silver plated with copper or copper plated with silver.

[0038]The metal particles in the invention may be particle-shaped,
rod-shaped or wire-shaped as long as they have a shorter diameter of a
nano size. The metal particles are preferably wire-shaped metal nanowires
in view of electrical conductivity and transparency.

[0039]Generally, metal nanowires indicate a substance having a linear
structure which is composed of a metallic element as a main constituent
and has a diameter of from an atomic scale to a nanometer (nm) size.

[0040]In order to form a long conductive path by one metal nanowire, the
metal nanowires in the invention have an average long axis length of
preferably not less than 3 μm, more preferably from 3 to 500 μm,
and still more preferably from 3 to 300 μm. In addition, the relative
standard deviation of the long axis length of the metal nanowires is
preferably 40% or less.

[0041]Moreover, the average short axis length of the metal nanowires is
not specifically limited but a smaller average short axis length is
preferred from a viewpoint of transparency, on the other hand, a larger
average short axis length is preferred from a viewpoint of electrical
conductivity. In the invention, the average short axis length of the
metal nanowires is preferably from 10 to 300 nm and more preferably from
30 to 200 nm. In addition, the relative standard deviation of the short
axis length of the metal nanowires is preferably 20% or less. The metal
nanowires in the conductive layer preferably contact each other, and more
preferably contact each other to be in the form of a mesh. A conductive
layer, in which the metal nanowires contact each other or contact each
other to be in the form of a mesh, can be easily formed employing the
liquid phase film formation method as described above.

[0042]With respect to definition of the long axis length, the short axis
length, the average long axis length, the average short axis length of
the metal nanowires in the invention, explanation will be made below.

[0043]When two straight lines parallel to each other are drawn to be
tangent to a projected image of the metal nanowire at two points on the
outer circumference of the projected image, a length of the longest
straight line segment of straight line segments connecting the two points
on the outer circumference of the projected image is defined as the long
axis length of the silver nanowire, and a length of a straight line
segment, which is a perpendicular bisector of the longest straight line
segment, and has both ends on the outer circumference of the projected
image, is defined as the short axis length of the silver nanowire.
Further, arithmetic averages of long axis lengths and short axis lengths
of the arbitrarily selected 100 metal nanowires are defined as the
average long axis length of the metal nanowires and the average short
axis length of the metal nanowires, respectively. The long axis length,
the short axis length, the average long axis length, the average short
axis length of the metal nanowires in the invention are determined
employing an electron micrograph of the metal nanowires being taken
through a transmission electron microscope (TEM).

[0044]In the present invention, there is no restriction in particular to a
metal nanowire manufacturing method. It is possible to manufacture metal
nanowires via well-known methods such as a liquid phase method or a gas
phase method. The concrete manufacturing method is not specifically
limited, and a conventional method can be applied. For example, the
manufacturing method of Ag nanowires may be referred to Adv. Mater.,
2002, 14, 833-837 and Chem. Mater., 2002, 14, 4736-4745; the
manufacturing method of Cu nanowires may be referred to Japanese Patent
O.P.I. Publication No. 2002-266007; while the manufacturing method of Co
nanowires may be referred to JP-A No. 2004-149871. The manufacturing
method of Ag nanowires can be preferably applied to the present
invention, since silver nanowires can be easily manufactured in an
aqueous solution and the electrical conductivity of silver is highest of
all metals.

[Metal Particle Removing Solution]

[0045]The composition of the metal particle removing solution used in the
invention is preferably that of a bleach fixer used in developing
treatment of a silver halide color photographic light sensitive material
from a viewpoint of safety in handling and etching property of metal
particles, particularly silver particles. The metal particle removing
solution is preferably an aqueous solution, however, it may be a solution
of an organic solvent such as ethanol, as long as the organic solvent can
dissolve beaching agents or fixing agents described later.

[0046]As a bleaching agent used in a bleach fixer, a well-known bleaching
agents are usable, and an organometallic complex salt such as an organic
complex salt of iron (III) (for example, a complex salt of
aminopolycarboxylic acids); an organic acid such as citric acid, tartaric
acid or a malic acid or the like; a persulfate and a hydrogen peroxide
are preferred.

[0048]These compounds may be any of sodium, potassium, lithium, and an
ammonium salt. With respect to SS-ethylenediamine disuccinic acid,
N-(2-carboxylatoethyl)-L-aspartic acid, β-alanine diacetic acid,
ethylenediamine tetraacetic acid, 1,3-diaminopropane tetraacetic acid,
and a methylimino diacetic acid among the above compounds, their iron
(III) complex salt is preferred. These ferric ion complex salts may be
used in the form of a complex, or a ferric salt such as ferric sulfate,
ferric chloride, ferric nitrate, ferric sulfate ammonium or ferric
phosphate may be used together with a chelating agent such as
aminopolycarboxylic acid to form a ferric ion complex salt in the
solution. Further, a chelating agent may be used exceeding an amount
necessary to form a complex salt with a ferric ion. Among the iron
complex salts, an iron (III)-aminopolycarboxylic acid complex salt is
preferred. The addition amount of the aminopolycarboxylic acid iron
complex salt is from 0.01 to 1.0 mol/liter, preferably from 0.05 to 0.50
mol/liter, more preferably from 0.10 to 0.50 mol/liter, and still more
preferably from 0.15 to 0.40 mol/liter.

[0049]A fixing agent used in a bleach fixer is a known fixing agent, i.e.,
a water soluble silver halide solvent, for example, a thiosulfate such as
sodium thiosulfate or ammonium thiosulfate; a thiocyanate such as sodium
thiocyanate or ammonium thiocyanate; a thioether compound such as
ethylene bisthioglycolic acid, 3,6-dithia-1,8-octane diol; or thiourea.
These fixing agents can be used singly or as an admixture of two or more
kinds thereof. Further, a special bleach fixer can be used which is
comprised of a combination of a fixing agent disclosed in Japanese Patent
O.P.I. Publication No. 55-155354 with a large amount of a halide such as
potassium iodide. In the present invention, a thiosulfate, especially
ammonium thiosulfate is preferred. The content of a fixing agent is
preferably from 0.3 to 2.0 mol and more preferably from 0.5 to 1.0 mol
per one liter of the bleach fixer.

[0050]The bleach fixer used in the present invention has a pH of
preferably from 3 to 8, and more preferably 4 to 7. In order to adjust
the pH, hydrochloric acid, sulfuric acid, nitric acid, bicarbonate,
ammonia, potassium hydroxide, sodium hydroxide, sodium carbonate or
potassium carbonate may be added, if desired

[0051]It is preferred that a viscosity increasing agent is added to the
bleach fixer used in the invention in order to give viscosity, which is
suitable for a printing method used, to the bleach fixer. Examples of the
viscosity increasing agent include a water soluble binder or fine silica
particles. The molecular weight of the water soluble binder can be
arbitrarily selected according to required viscosity of the bleach fixer.

[0052]In the invention, the viscosity of the metal particle removing
solution is preferably from 0.01 to 1000 Pas and more preferably from
0.05 to 500 Pas.

[0053]In addition to the water soluble binder, various defoaming agents or
surfactants, polyvinyl pyrrolidone or an organic solvent can be contained
in the bleaching fixer. It is preferred that the bleach fixer contains,
as a preserving agent, a sulfite ion releasing compound such as a sulfite
(for example, sodium sulfite, potassium sulfite or ammonium sulfite); a
bisulfite (for example, ammonium bisulfite, sodium bisulfite or potassium
bisulfite) or a metabisulfite (for example, potassium metabisulfite,
sodium metabisulfite or ammonium metabisulfite); or an arylsulfinic acid
such as p-toluene sulfinic acid or m-carboxybenzene sulfinic acid. It is
preferred that these compounds are contained in the bleach fixer in an
amount of approximately 0.02 to 1.0 mol/liter in terms of a sulfite ion
or a sulfinate ion.

[0054]Beside the compounds described above, ascorbic acid, a carbonyl
bisulfite adduct or a carbonyl compound may be added as the preserving
agent. Further, a buffering agent, a chelating agent, a defoaming agent
or a mildew-proofing agent may also added, if desired.

[Water Soluble Binder]

[0055]As a water soluble binder used in the invention, there are mentioned
a synthetic water soluble binder and a natural water soluble binder.

[0056]As the synthetic water soluble binder, there are mentioned those
having in the molecule a nonionic group, those having in the molecule an
anionic group, and those having in the molecule a nonionic group and an
anionic group. Examples of the nonionic group include an ether group, an
ethyleneoxy group and a hydroxyl group, and examples of the anionic group
include a sulfonic acid group or its salt group, a carboxyl group or its
salt group and a phosphoric acid group or its salt group.

[0057]The synthetic water soluble binder may be a homopolymer or a
copolymer of one monomer unit with one or more kinds of other monomer
units. The copolymer may be a copolymer having a hydrophobic monomer unit
as long as it retains water solubility, although it is necessary that the
content of the hydrophobic monomer unit in the copolymer is in the range
that does not have an adverse effect.

[0058]As the natural water soluble binder, there are mentioned those
having in the molecule a nonionic group, those having in the molecule an
anionic group, and those having in the molecule a nonionic group and an
anionic group. The natural water soluble binder in the invention is
described in detain in "Suiyoseikobunshi Mizubunsangata Jusi no
Sogogijutsu Siryoshuu" (published by Keiei Kaihatu Senta Shuppanbu). The
natural water soluble binder is preferably lignin, starch, pullulan,
cellulose, alginic acid, dextran, dextrin, guar gum, gum arabic, pectin,
casein, agar, xanthan gum, cyclodextrin, locust bean gum, tragacanth gum,
carrageenan, glycogen, laminaran, lichenin, nigeran or their derivative.

[0059]As the derivatives of the natural water soluble binder are preferred
those sulfonated, those carboxylated, those phosphorylated, those
sulfoalkylated, those carboxyalkylated, those alkylphosphorylated and
their salt, those modified with polyoxyalkylene oxide (for example,
polyethylene oxide polyglycerin or polypropylene oxide), or those
alkylated (for example, methylated, ethylated or benzylated).

[0060]Among the natural water soluble binders, glucose polymers or its
derivatives are preferred. Among the glucose polymers or its derivatives,
starch, glycogen, cellulose, lichenin, dextran, dextrin, cyclodextrin and
nigeran are preferred, and cellulose, dextrin, cyclodextrin and their
derivatives are especially preferred.

[0061]Examples of the cellulose derivatives include methylcellulose,
hydroxyethylcellulose, and sodium carboxymethylcellulose (hereinafter
also referred to as CMC). Among these, CMC is preferred since it is
highly soluble in water. The molecular weight of the water soluble binder
in the invention can be arbitrarily selected according to viscosity to be
required.

[Pattern Printing]

[0062]As a method of pattern printing the metal particle removing solution
in the invention, there are printing methods such as a letterpress
(typographic) printing method, a porous (screen) printing method, a
lithographic (offset) printing method, an intaglio (gravure) printing
method, a spray printing method and an ink-jet printing method. The metal
particle removing solution in the invention is pattern printed on a
portion of the conductive layer in the invention containing metal
particles, which is unnecessary to form a pattern electrode, and washed
to remove the metal particles at that portion, whereby a pattern
electrode can be easily formed.

[0063]The pattern printing thickness of the metal particle removing
solution in the invention can be appropriately varied due to thickness or
area of a metal particle-containing conductive layer to be removed, but
is preferably from 10 μm to 2 mm from a viewpoint of reactivity
between the metal particle removing solution and the metal particles in
the conductive layer or prevention of lateral spread of the metal
particle removing solution printed.

[0064]The washing in the invention, which is carried out after the pattern
printing of the metal particle removing solution, is not specifically
limited but is preferably is carried out employing water. It is also
preferred that the washing is carried out with flowing water or is
carried out in water with stirring. The washing time is time during which
the metal particle removing solution is completely washed off, and is
preferably at least 10 seconds.

[Pattern Electrode]

[0065]The pattern electrode in the invention refers to an electrode having
a conductive portion comprised of a conductive layer containing the metal
particles described previously and a non-conductive portion in which the
metal particle removing solution is pattern printed on the conductive
layer containing the metal particles to remove the metal particles,
employing the pattern electrode manufacturing method of the invention.

[0066]It is desirable that the total light transmittance of the conductive
portion in the pattern electrode of the present invention is at least
60%, preferably at least 70%, and more preferably at least 80%. The total
light transmittance can be determined according to a well-known method
employing a spectrophotometer and the like.

[0067]The electrical resistance value of the conductive portion in the
pattern electrode of the invention is preferably at most 102
Ω/quadrature, and more preferably at most 10 Ω/quadrature
in terms of surface specific resistance. The surface specific resistance
can be determined for example, based on JIS K6911, ASTM D257. Further, it
can be easily determined employing a commercially available surface
resistance meter.

[0068]An anchor coat or a hard coat can be provided in the pattern
electrode of the invention. Further, a conductive layer containing a
conductive polymer or metal oxides may be provided if necessary.

[0069]The pattern electrode of the invention is preferably applied to a
transparent electrode for LCD, an electroluminescence element, a plasma
display, an electrochromic display, a solar cell or a touch panel; an
electronic paper or an electromagnetic wave shielding material.

Examples

[0070]Next, the present invention will be explained employing examples,
but the invention is not specifically limited thereto. In the examples,
"%" represents "% by mass", unless otherwise specified.

[Preparation of Pattern Electrode TCF-1 (Comparative Example)]

[0071]A solution of silver nanowires with an average short axis length of
75 nm and an average long axis length of 35 μm as metal particles was
prepared employing polyvinyl pyrrolidone K30 with a molecular weight of
50,000 (produced by ISP Co., Ltd.) according to the method described in
Adv. Mater., 2002, 14, 833-837, and filtered employing a ultrafiltration
membrane, and washed with water to obtain the silver nanowires. The
resulting silver nanowires were re-dispersed in an aqueous solution in
which hydroxypropylmethyl cellulose 60SH-50 (produced by Shin-etsu Kagaku
Kogyo Co., Ltd.) was contained in an amount of 25% by mass based on the
amount of the silver to obtain a silver nanowire dispersion solution.

[0072]The silver nanowire dispersion solution was applied onto a
polyethylene terephthalate film substrate subjected to adhesion assisting
treatment (hereinafter referred to as highly adhesive polyethylene
terephthalate film substrate), trade name Cosmoshine A4100 (produced by
Toyobo Co., Ltd.), using a spin coater, and dried to form a silver
nanowire layer with a coating amount of 0.05 g/m2. Thereafter, the
resulting silver nanowire layer was subjected to calendar treatment, and
then a stripe-shaped Pattern Electrode TCF-1 having a conductive portion
pattern with a width of 10 mm and a pattern interval of 10 mm, was
prepared according to well-known photolithography. The Pattern Electrode
TCF-1 thus prepared was visually observed. No residual metal particles
were observed in the non-conductive portion, however, both ends in the
width direction of the conductive portion in the stripe-shaped pattern
were etched by approximately 0.5 mm by width, and width reduction of the
conductive portion was observed.

[Preparation of Pattern Electrode TCF-2 (Comparative Example)]

[0073]A printing plate having a stripe-shaped pattern with a printing
pattern width of 10 mm and a pattern interval of 10 mm was mounted on a
gravure coating machine, K Printing Proofer (produced by MATSUO SANGYO
Co., Ltd.), and gravure printing was carried out employing a silver
nanowire dispersion solution used in the preparation of TCF-1 above,
whose viscosity was adjusted to 1 Pas (1000 cP) with sodium
carboxymethylcellulose (C5013 produced by SIGMA-ALDRICH Ca, Ltd.,
hereinafter also referred to as CMC), while controlling the printing
times, so that pattern portions with a silver nanowire coating amount of
0.05 g/m2 were printed on a highly adhesive polyethylene
terephthalate film substrate, trade name Cosmoshine A4100 (produced by
Toyobo Co., Ltd.). Thus, a stripe-shaped Pattern Electrode TCF-2 was
prepared.

[0075]Water was added to the above composition to make a 1 liter solution
and adjusted to a pH of 5.5 with sulfuric acid or aqueous ammonia. Thus,
Metal Particle Removing Solution BF-1 was prepared.

[0076]The silver nanowire dispersion solution used in the preparation of
TCF-1 above was applied onto a highly adhesive polyethylene terephthalate
film substrate, trade name Cosmoshine A4100 (produced by Toyobo Co.,
Ltd.), using a spin coater, and dried to form a silver nanowire layer
with a coating amount of 0.05 g/m2. Thereafter, the resulting silver
nanowire layer was subjected to calendar treatment. A printing plate
having a stripe-shaped pattern with a printing pattern width of 10 mm and
a pattern interval of 10 mm was mounted on a gravure coating machine, K
Printing Proofer (produced by MATSUO SANGYO Co., Ltd.), and gravure
printing was carried out employing a metal particle removing solution in
which the viscosity of Metal Particle Removing Solution BF-1 was adjusted
to 0.5 Pas (500 cP) with CMC, while controlling the printing times, so
that the metal particle removing solution was applied on the silver
nanowire layer to give a coating thickness of 30 μm. After printing,
the resulting printed material was allowed to stand for 1 minute, and
then washed for 1 minute with flowing water. Thus, a stripe-shaped
Pattern Electrode TCF-3 was prepared.

[Preparation of Pattern Electrode TCF-4 (Inventive Example)]

[0077]Printing was carried out in the same manner as in Pattern Electrode
TCF-3, except that screen printing was carried out instead of gravure
printing, employing a polyester mesh for screen printing 255T (produced
by Mitani Micronics Co., Ltd.) having a stripe-shaped pattern with a
printing pattern width of 10 mm and a pattern interval of 10 mm and a
metal particle removing solution in which the viscosity of the Metal
Particle Removing Solution BF-1 prepared in TCF-3 was adjusted to 10 Pas
(10000 cP) with CMC, so that the metal particle removing solution was
applied on the silver nanowire layer to give a coating thickness of 30
μm. After printing, the resulting printed material was allowed to
stand for 1 minute, and then washed for 1 minute with flowing water.
Thus, a stripe-shaped Pattern Electrode TCF-4 was prepared.

[Preparation of Pattern Electrode TCF-5 (Inventive Example)]

[0078]Printing was carried out in the same manner as in Pattern Electrode
TCF-3, except that ink jet printing was carried out instead of gravure
printing, employing an ink jet printer and a metal particle removing
solution in which the viscosity of the Metal Particle Removing Solution
BF-1 prepared in TCF-3 was adjusted to 30 Pas (30 cP) with CMC to form a
stripe-shaped pattern with a printing pattern width of 10 mm and a
pattern interval of 10 mm, so that the metal particle removing solution
was applied on the silver nanowire layer to give a coating thickness of
30 μm. After printing, the resulting printed material was allowed to
stand for 1 minute, and then washed for 1 minute with flowing water.
Thus, a stripe-shaped Pattern Electrode TCF-4 was prepared.

[Preparation of Pattern Electrode TCF-6 (Inventive Example)]

[0079]A stripe-shaped Pattern Electrode TCF-6 was prepared in the same
manner as in TCF-4, except that a metal particle removing solution in
which the viscosity of the Metal Particle Removing Solution BF-1 was
adjusted to 10 Pas (10000 cP) with a viscosity increasing agent Aerosil
#200 (silica particles, produced by Nippon Aerosil Co., Ltd.) used. The
screen mesh after printing was observed, and partial clogging of the mesh
was observed.

[Preparation of Pattern Electrode TCF-7 (Inventive Example)]

[0080]As the substrate, a biaxially stretched polyethylene terephthalate
film, trade name Lumirror U 46 (produced by Toray Co., Ltd.) having a
hydrophilic layer on one side thereof was employed, the hydrophilic layer
being formed by hydrophilization treatment. The following self-organizing
silver particle layer formation solution C-1 was coated as metal
particles on the hydrophilic layer of the film, allowed to stand at
25° C. for 1 minute so that the silver particles was
self-organized in a network form to form a random network silver particle
layer, and processed at 150° C. for 1 minute. Thereafter, the
resulting film was immersed in 25° C. acetone (Special grade,
produced by NACALAI TESQUE, INC.) for 30 seconds, taken out from the
acetone and dried at 25° C. for 1 minute. Subsequently, the
resulting film was immersed in a 25° C. 1N (1 mol/L) hydrochloric
acid solution, N/10-hydrochloric acid (produced by NACALAI TESQUE, INC.)
for 1 minute, taken out from the solution, and dried at 150° C.
for 1 minute. Thus, a network silver particle layer formation film was
prepared.

[0082]Like TCP-3, a printing plate having a stripe-shaped pattern with a
printing pattern width of 10 mm and a pattern interval of 10 mm was
mounted on a gravure coating machine, K Printing Proofer (produced by
MATSUO SANGYO Co., Ltd.), and gravure printing was carried out employing
a metal particle removing solution in which the viscosity of Metal
Particle Removing Solution BF-1 was adjusted to 0.5 Pas (500 cP) with
CMC, while controlling the printing times, so that the metal particle
removing solution was applied on the network silver particle layer
formation film layer to give a coating thickness of 30 μm. After
printing, the resulting printed material was allowed to stand for 3
minutes, and then washed for 1 minute with flowing water. Thus, a
stripe-shaped Pattern Electrode TCF-7 was prepared.

[Preparation of Pattern Electrode TCF-8 (Inventive Example)]

[0083]A stripe-shaped Pattern Electrode TCF-8 was prepared in the same
manner as in TCF-3, except that copper nanowires with an average of 20 nm
and a average length of 10 μm, which was prepared according to the
method as described in Japanese Patent O.P.I. Publication No. 202-266007
was used instead of the silver nanowires.

[Preparation of Pattern Electrode TCF-9 (Inventive Example)]

[0084]The silver nanowire dispersion solution used in the preparation of
TCF-1 above was coated onto a hard coat layer of a polyethylene
terephthalate film substrate subjected to hard coat processing, using a
spin coater, and dried to form a silver nanowire layer with a coating
amount of 0.05 g/m2. Thereafter, the resulting silver nanowire layer
was subjected to calendar treatment. Further, a UV curable resin Optomer
NN (produced by JSR Co., Ltd.) was coated on an adhesive layer of a
highly adhesive polyethylene terephthalate film substrate, employing a
spin coater, so as to form a resin layer with a thickness of 3 μm.
Subsequently, the silver nanowire layer coated film substrate prepared
above was laminated under pressure onto the resin layer so that the resin
layer face the silver nanowire layer, and the resulting laminate was
subjected to UV irradiation from the substrate side of the highly
adhesive polyethylene terephthalate film substrate to cure the UV curable
resin, and then the hard coat-processed film substrate was separated from
the laminate to obtain a silver nanowire transfer film. Like TCP-3, a
printing plate having a stripe-shaped pattern with a printing pattern
width of 10 mm and a pattern interval of 10 mm was mounted on a gravure
coating machine, K Printing Proofer (produced by MATSUO SANGYO Co.,
Ltd.), and gravure printing was carried out employing a metal particle
removing solution in which the viscosity of Metal Particle Removing
Solution BF-1 was adjusted to 0.5 Pas (500 cP) with CMC, while
controlling the printing times, so that the metal particle removing
solution was applied on the silver nanowire layer of the silver nanowire
transfer film to give a coating thickness of 30 μm. After printing,
the resulting printed material was allowed to stand for 1 minute, and
then washed for 1 minute with flowing water. Thus, a stripe-shaped
Pattern Electrode TCF-9 was prepared.

[0086]Water was added to the above composition to make a 1 liter solution
and adjusted to a pH of 5.0 with potassium carbonate or glacial acetic
acid.

[0087]A stripe-shaped Pattern Electrode TCF-10 was prepared in the same
manner as in TCF-3, except that the metal particle removing solution
BF-2, whose viscosity was adjusted to 0.5 Pas (500 cP) with CMC, was used
instead of the metal particle removing solution BF-1.

[Preparation of Pattern Electrode TCF-11 (Inventive Example)]

[0088]Screen printing was carried out employing a polyester mesh for
screen printing MFT 325 (produced by Mitani Micronics Co., Ltd.) having a
grid pattern with a printing pattern width of 25 μm and a pattern
interval of 500 μm and a silver nanoparticle containing paste MDot-SLP
(produced by Mitsuboshi Belt Co., Ltd.), so that the grid pattern layer
was formed on a highly adhesive polyethylene terephthalate film
substrate, trade name Cosmoshine A4100 (produced by Toyobo Co., Ltd.),
and the printed matter was heated at 120° C. for 30 minutes to
obtain a silver grid film. Subsequently, like TCP-3, a printing plate
having a stripe-shaped pattern with a printing pattern width of 10 mm and
a pattern interval of 10 mm was mounted on a gravure coating machine, K
Printing Proofer (produced by MATSUO SANGYO Co., Ltd.), and gravure
printing was carried out employing a metal particle removing solution in
which the viscosity of Metal Particle Removing Solution BF-1 was adjusted
to 0.5 Pas (500 cP) with CMC, while controlling the printing times, so
that the metal particle removing solution was applied on the silver grid
pattern layer of the silver grid film to give a coating thickness of 30
μm. After printing, the resulting printed material was allowed to
stand for 3 minutes, and then washed for 1 minute with flowing water.
Thus, a stripe-shaped Pattern Electrode TCF-11 was prepared.

[0089]The inventive pattern electrodes 3 through 11 prepared above were
visually observed, and it proved that there were no residual metal
particles in the non-conductive portions thereof, and no width reduction
in the conductive portions thereof, showing an excellent etching
property.

<<Evaluation of Pattern Electrode>>

[0090]The surface specific resistance and transmittance of pattern
electrodes 1 through 11 were evaluated according to the following method.

(Surface Specific Resistance)

[0091]The surface specific resistance was measured by means of a
resistivity measurement meter Loresta GP produced by Dia Instruments Co.,
Ltd., and the surface specific resistance at the stripe-shaped pattern
portions was measured employing a four terminal method.

(Light Transmittance)

[0092]With respect to light transmittance, the total light transmittance
of the conductive portion of the stripe-shaped pattern electrode was
determined through AUTOMATIC HAZE METER (MODEL TC-HIIIDP) produced by
Tokyo Denshoku Co., Ltd.

[0093]As is apparent from table 1, Comparative Pattern Electrode TCF-1
exhibits lowering of light transmittance due to residual resist at the
conductive portion, elevation of resistance at the conductive portion due
to silver nanowire separation, and pattern width reduction due to
over-etching, and Comparative Pattern Electrode TCF-2 exhibits lowering
of light transmittance resulting from the binder for adjusting viscosity
and marked elevation of resistance at the conductive portion resulting
from increase in contact resistance between the silver nanowires. On the
other hand, Inventive Pattern Electrodes exhibit high conductivity (see
surface specific resistance), high transparency (see light transmittance)
and excellent etching property without residual metal particles or
without reduction of the pattern width. In Inventive Pattern Electrode
TCF-6, clogging of the screen mesh after printing, which is considered to
be due to silica particles used, is observed, however, the clogging
matter is easily removed by washing, and completely removed by employing
a water soluble binder as a viscosity increasing agent. In Inventive
Pattern Electrode TCF-7 or 11, retention time, during which after
printing of the metal particle removing solution on the conductive
portions, the printed metal particle removing solution is retained on the
conductive portions, is a little long, however, when the retention time
is taken longer, etching can be carried out without problem, and when
metal particles having a large specific area such as metal nanowires are
used, etching can be carried out at shorter retention time.